The National Medical Research Council, a Government body, said the survey results will form the basis of a future campaign to encourage people to volunteer for clinical trials.

The tests are considered critical in evaluating the effectiveness and safety of medicines.

But some researchers say trials can be stalled because of a shortage of volunteers.Experts say many people express concern that their confidential information will be leaked, while others worry about side effects.

The push for volunteers comes at a time when the number of clinical trials here is rising.

The Health Sciences Authority said 253 new trials were recorded last year, up from 99 in 1998. Official figures are not available, but the number of people involved in clinical trials is estimated to run into the tens of thousands.

Read the full story in Friday's edition of The Straits Times.